This invention relates to a remote keyless entry system.
JP-A-8-284505 (hereinafter called the xe2x80x9creference 1xe2x80x9d) describes a remote keyless entry system that executes 2-way communications, sends to an operation apparatus side a notice representing whether or not the operation is executed, and sends the report to a user. However, this reference does not describe a transfer data rate. Therefore, the reference does not take into account the decreasing of a communication distance in 2-way communications when it utilizes a weak radio wave. In other words, when communications fail at a place of a certain distance in the known reference 1, the operator must come into the range of the communication distance and must once again try communications.
JP-A-9-209630 (hereinafter called the xe2x80x9creference 2xe2x80x9d) describes another remote keyless entry system. A portable transmitter of this system intermittently generates a radio wave modulated by an identification code, and when the user having the portable transmitter walks up to a car, a receiver mounted to the car receives the radio wave and releases the door lock when the identification code is correct. A time zone in which the portable transmitter automatically emits the radio wave for releasing the door lock can be set in order to minimize battery consumption.
Though the reference 2 limits the automatic transmission time zone, the transmitter executes an automatic output operation in a predetermined time zone either daily or on predetermined days of the week. Therefore, battery consumption is greater than when this automatic transmission operation is not made. originally, a driver of a car desires to make the automatic door lock when the driver walks up to the car while holding things with his or her both hands and cannot take out a terminal board kept in the pocket, or when the driver approaches the car with an umbrella spread. Usually, when the driver returns to the car while holding things with both hands or with an umbrella spread, it does not take a long time before he reaches the car, and it is only five to 10 minutes, or about 60 minutes or so, at the longest. Therefore, it is not economical from the aspect of battery consumption to execute the automatic output operation in the predetermined time zone as is made in the reference 2.
JP-A-4-315684 (hereinafter called the xe2x80x9creference 3xe2x80x9d) describes a remote keyless entry system in which a display is provided to a terminal board to display the state of a car. The driver of the car always keeps the key, and although the display is provided to the terminal board of the remote keyless entry system, the driver cannot confirm the time when he desires to check the time. Even when the time for operating the engine is determined in advance, the driver must take the trouble in walking up to the location of the car to start the engine.
It is an object of the present invention to provide a novel and improved remote keyless entry system.
It is the first object of the present invention to provide a keyless entry system that can be operated even when an operator does not move into a communication distance range. To accomplish this object, a data generation circuit having different data rates and a selection circuit of transmission data are provided to a terminal board so that the data transfer rate can be changed when long distance communication is necessary. This data generation circuit executes transmission of a high-speed data rate at first. When no response to the high-speed data is received, the data generation circuit again executes transmission by switching the data rate.
It is the second object of the present invention to provide a remote keyless entry system that can be operated even when both hands of an operator or a driver are full, minimizes battery consumption and reduces the frequency of the battery exchange. To accomplish this object, an automatic output operation button and an automatic output time setting circuit are provided to a terminal board, and a transmission circuit capable of automatic transmission for a predetermined time from a set operation is further provided. The automatic output time setting circuit sets the time at which an automatic output operation is made. The automatic output operation button executes activation of the automatic output operation. The terminal board conducts the automatic output operation from the point of time at which the activation operation is effected, and then stops its operation. When the driver approaches the car within the set time, door lock of the car is released without the door lock release operation.
It is the third object of the present invention to provide a remote keyless entry system that makes it possible to confirm the time by a terminal board. To accomplish this object, a timepiece circuit is provided to a terminal board comprising an operation button and a communication circuit. The terminal board is so controlled as to execute an operation content set in advance, at a predetermined time.